The ghosts of ancient Afghanistan

In 1971, a team of French archaeologists discovered a sculpture in fragments at a site by the river Oxus in northern Afghanistan. It was restored and placed in the National Museum in Kabul. Then, a decade ago, it was smashed all over again, this time deliberately – by the Taliban, who were also demolishing the colossal Buddhas at Bamiyan, in the centre of the country. Those vast masterpieces of religious art are gone for ever, but this wonder of nudity was luckier. Afghan experts have now pieced it together again – and sent it around the world, to show off the richness of a country the world thinks of only as a vast alien battleground; or, in the subtle words of our defence secretary Liam Fox, "a broken 13th-century country".

The twice-rescued young man greets you at the start of Afghanistan: Crossroads of the Ancient World, the British Museum's compelling new show. There's no mistaking the beauty of this alabaster nude, who would be arresting even without his story of survival. The history of Afghanistan, this exhibition hints, is vast, complex and astounding. Its epic nature is shown by the fact that this show covers just a few ancient centuries, ending in the first century AD. But what centuries they were.

One of the most remarkable things about the youth carved in alabaster is the fact that he's an ancient Greek. How did he end up in Afghanistan? Well, he was found at an ancient Greek city discovered near the Oxus by French archaeologists in the 1960s. They partially excavated the city, clearly Hellenic in its art and architecture, until the Soviet invasion drove them away in 1979, leaving the site to be torn apart by looters.

Locals called the city Ai Khamun, Lady Moon, from a legend about a princess who lived in a fortress on the site. The remains of Lady Moon city, on show in this exhibition, are as stupendous as they are delicate. The huge flowery bloom of a Corinthian capital (the decorated top of a column) stands next to leaf-like terracotta ornaments overlooking a sundial shaped into a hollow sphere. A bronze Heracles, musclebound and fierce, is powerful proof that the Greek gods and heroes penetrated this far into Asia....